The present invention relates generally to a clutch for a transmission. More particularly, the invention relates to a friction clutch for a transmission wherein the pulling of a release bearing allows the disengagement of the clutch.
A conventional friction clutch includes a diaphragm spring which has a release lever, integrally formed on the inner end thereof, for engaging with a release bearing assembly directly, the outer end of this spring is supported by a clutch cover. The diaphragm spring provides pressure directly to a pressure plate which is required to hold a friction disc against a flywheel. The pulling of the release bearing tends to cause the diaphragm spring to become deformed, thereby weakening the pressure exerted to the pressure plate. This pressure is necessary to release, or disengage the clutch.
Moreover, in another type of conventional clutch, a release bearing assembly includes an inner sleeve member and an outer sleeve member. One of these sleeves (usually the inner sleeve) engages with the inner periphery of the diaphragm spring of a clutch cover assembly installed on a flywheel. The diaphragm spring and the inner sleeve are fastened in this engaged position.
However, in the above clutches, the rigidity of the diaphragm spring is dependent upon the spring properties thereof and therefore the rigidity of the lever integrally provided on the end of the diaphragm spring is also determined by same. For these reasons, a rigidity of lever sufficient to disengage the clutch is not obtained. It will be appreciated that the pulling of the lever by the release bearing assembly causes it to be deformed greatly and therefore the clutch does not disengage sufficiently.
Further, the fastening positions of the diaphragm spring to the inner sleeve are invisible. The positioning between the two during assembly and disassembly thereof is relatively difficult. The direct connecting of the diaphragm to the release bearing assembly tends to increase the thrust load on the inner sleeve or the outer sleeve, thereby inducing abnormal wear of the release bearing.